Patient-rotation system with center-of-gravity assembly

ABSTRACT

A system for turning a person from a supine position to a prone position and vice versa includes opposing patient support platens each coupled to a corresponding end of a first and a second COG assembly, the first and second COG assemblies each coupled to a corresponding one of a pair of spindles, each one of the spindles disposed on a corresponding lift column. Embodiments described herein provide for an axis of rotation that is adjustable with respect to the plane of either an upper or lower support platen. Embodiments provide for adjusting the separation distance between the axis of rotation and the center of gravity defined by the combination of the person and the supporting platens.

CROSS REFERENCE TO RELATED APPLICATIONS

The present patent application claims benefit of U.S. ProvisionalApplication Ser. No. 61/165,897 filed on 1 Apr. 2009 entitledPatient-Transfer System with Horizontal-Center-of-Gravity (COG)Rotational Assembly, incorporated herein by reference.

FIELD OF ART

This patent application is directed to a system for rotating,transferring, positioning, or lifting a patient for purposes ofperforming a medical procedure where a patient is rotated from a supineposition to a prone position, and vice versa. The apparatus may be usedfor transferring a patient to and from an operating table.

BACKGROUND

Generally, surgeries and procedures performed to the posterior of apatient require the patient to be positioned in a prone position toprovide access to a surgical site. Prior to performing the surgery,protocol typically requires that the patient be anesthetized andintubated while lying on their back. For the vast majority of backsurgeries performed in the United States today, most patients are stillanesthetized on a gurney, and then manually lifted, inverted anddeposited on an operating table.

There are many challenges associated with the transfer of the patient tothe operating table from the gurney, and vice versa. The manual processof transfer is physically demanding and non-physiologic for the staff,and is potentially unsafe for the anesthetized patient. For instance, ananesthetized patient who is in an unconscious state has absolutely nocontrol over their appendages and head, which all have a tendency toflop-down from gravity. If any appendages are not properly supported, itis possible to break, dislocate, or otherwise injure the patient's neck,shoulder area, and/or appendages while manually lifting and invertingthe patient. Additionally, the patient may have a preexisting disease orinjury to the spine, which if moved or twisted improperly could causedamage or paralysis to the patient. Thus, the staff must remain vigilantto properly support the appendages and body of the patient each time thepatient is lifted and inverted. There is also a potential toaccidentally lose control of or drop a patient incurring injury to thepatient and/or staff.

Additionally, an anesthetized patient assumes “dead weight” which makesthat person feel heavier. The weight of the patient exposes staffmembers, such as nurses, assistants, and doctors, to injuries whenlifting the patient. Often times a staff member must lean across agurney or operating room table exposing themselves to lifting injuries.Sometimes, the weight of the patient is not evenly distributedpotentially risking injury to a staff member or patient. Accordingly,liability issues arise when patients are dropped or injured while beingoriented on the operating table while sedated. Doctors and hospitals arealso exposed to liability when operating staff are injured lifting andpositioning sedated patients.

A further potential problem associated with turning the patient fromhis/her stomach or back involves the potential for patient motion orstaff interference with life-support and life-monitoring systems thatmay be attached to the patient, such as an intravenous line, a catheter,electrode monitoring lines for monitoring the patient's vital signs, andan endotracheal tube for the purposes of administering oxygen and/oranesthesia to the patient. If any one of these life-support orlife-monitoring systems is pulled out, crimped, or twisted, it caninjure the patient and/or the operating staff.

Still another complication associated with manually lifting andinverting a patient onto an operating table for back surgery involvespositioning the patient in proper alignment on the table. Some patientsare placed on a “Wilson Frame” to properly align the back properlythereby and enhancing proper ventilation. The Wilson Frame allows theabdomen to hang pendulous and free. It is often difficult to manuallymanipulate the patient once placed onto the operating table to ensureproper alignment with the Wilson Frame underneath the patient.

Other ancillary problems involve positioning of the head, chest, andlegs with proper support and access for devices such as the endotrachealtube. Anthropometric considerations, such as patient size, includingweight and width, cause the operating staff to ensure that properpadding and elevations are used to support the head, chest, and legs. Itis not uncommon to find operating staff stuffing pillows or beddingunderneath a patient to adjust for different anthropometric features ofa patient.

Attempts have been made to solve the transfer problems described aboveincluding systems which can turn rotate a patient. Unfortunately, manysuch systems for turning a patient have an axis of rotation and a centerof gravity that are different. In such systems the separation of therotation axis and the center of gravity make the system “top-heavy”, orunbalanced, and therefore it is difficult to manually turn a patient.Furthermore, the unbalanced load creates greater stresses on themechanical equipment and presents greater risk of mechanical failure tothe patient.

SUMMARY

Described herein is a patient-safety-transfer system for rotating,transferring, positioning, or lifting a patient for purposes ofperforming a medical procedure where a patient is rotated from a supineposition to a prone position, and vice versa. The system may be used forlifting, positioning, rotating and/or transferring an anesthetizedpatient for purposes of performing posterior surgery, and relatedmedical procedures.

In one embodiment, the system includes first and secondcenter-of-gravity (COG) assemblies. Opposing patient-support platens—ananterior platen (for abutting the front portions of the patient) and aposterior platen (for abutting back portions of the patient)—are coupledto a corresponding end of the first and second COG assemblies. The firstand second COG assemblies are each coupled to a corresponding one of apair of floating-spindle heads. Each one of the floating-spindle headsis disposed on a corresponding lift column. The COG assemblies providefor an axis of rotation that is outside the plane of platens upon whichthe patient is disposed. Specifically, the system provides a rotationaxis outside the plane of either subjacent or superjacentpatient-support platform, and more closely aligned with thecenter-of-gravity.

In other embodiments, the COG assemblies adjust a separation distancebetween the axis of rotation and the center-of-gravity defined by acombination of the patient and the supporting platens.

Achieving controlled patient pad compression is a pre-condition tosafely clamp, secure, pick up, and rotate a patient 180 degrees fromprone to supine position, or supine to prone position. To achieveoptimal compression, in another embodiment, a lost-motion-over-travelsystem prevents the platens from continuing to travel toward the patientwhen lowering a platen toward to the patient, once optimal compressionforces exerted on the patient via a platen (and/or the platen'sconstituent-support padding) is obtained.

In yet another embodiment, registration plates, coupled to the system,conveniently align the attachment mechanisms of each COG assembly withdistal ends of one or more platens. For instance, when the anteriorplaten is placed on the surface of an operating table and is detachedfrom the system, the distal ends of the anterior platen maytelescopically extend beyond the ends of the table. When retrieving apatient from the operating table, the registration plates allow formedical staff to align the system so that it straddles the operatingtable with the attachment mechanisms of the COG assembly in alignmentwith platen tubes (or other complimentary attachment mechanisms) locatedat the distal ends of the anterior platen.

The system eliminates the need for operating room staff to manually liftand place an anesthetized patient in prone or supine positions. Thesystem also provides safety for the patient and for medical staffcharged with turning the patient. The system includes powered-liftcolumns that lift and lower platens between which a patient is disposed.The powered-lift columns, in embodiments described herein, are typicallyelectrically powered, but it is appreciated by those skilled in the arthaving the benefit this disclosure, that these powered-lift columns arenot so limited and may be powered by any suitable means including butnot limited to hydraulics and pneumatics.

Various embodiments described herein provide a solution to achieve anoptimum center-of-gravity (i.e., a balanced load) between platens,having a patient sandwiched therein, to the rotation axis of tworotation spindles. With an optimized center-of-gravity relative to thespindle axis, personnel are provided with the optimal-balanced load formanually rotating the patient 180 degrees. This provides a safecondition for both patient and staff while the patient is rotated fromthe supine to prone position, or from the prone to supine position.

Various embodiments of the present invention include several mechanicalelements, assemblies and subsystems, such as, but not limited to,dual-rack-and-pinion subsystems, lost motion devices, gas shockabsorbers, and ratchet and pawl subsystems. These mechanical elements,assemblies, and subsystems are combined in a unique manner to provide apatient safety transfer system operable to safely rotate a patient froma supine to prone position, and from a prone to supine position.

Regarding the exemplary dual-rack-and-pinions, each of these allow a topset of racks to extend simultaneously with the lower set of racks. Thisis used in the COG assembly (described in greater below) and provides aself-centering function. With respect to lost-motion devices, in mostapplications the driven load stops moving when it contacts a fixed stopand the powered device continues to lower in a free state.

Gas-shock absorbers are used to counter-act large weights in manymechanisms such as a rear hatch door in a vehicle. The gas-shockabsorbers are sized to each application in order to reduce free energycaused by gravity as well as provide an ergonomic, realistic amount ofenergy for human beings to safely perform a given manual function, suchas, in the embodiments, rotating a patient from supine to prone and viceversa.

Ratchet-and-pawl systems provide mechanisms with the ability toback-drive in one direction and catch in the opposite direction ofrotation as is used in the adjustable frame system.

The various embodiments are part of an illustrativepatient-safety-transfer system that includes a lift-column assembly thatis mounted to a portable-caster-base assembly. Each caster-base assemblyis tied to the other with a drawbar that has an operating position (asshown FIG. 1) and a collapsed-storage position (not shown). Afloating-spindle-head assembly is mounted on top of each lift-columnassembly. A COG assembly is mounted to the inboard side of eachfloating-spindle-head assembly with a spindle shaft allowing forrotation of the COG assembly. The COG assembly adjusts open and shutwith a dual-rack-and-pinion device to open both or close both posteriorand anterior shafts simultaneously. A platen-latch assembly is mountedto each end of the COG assembly to manually lock onto the platen tubeslocated at the distal ends of each platen. Each COG assembly has oneplaten-latch assembly for the posterior platen and one latch assemblyfor the anterior platen.

One posterior platen is used for the posterior side of patients and hastwo telescoping shafts to provide a safety distance (approximately 6.0inches in one embodiment, but other suitable distances may beimplemented) between the COG-platen latches and the patient, while thepatient is lying on the platen. Platen-tube extensions can be collapsedso as to be flush with an operating table when a transfer or rotation iscomplete in order to provide patient access during an operating roomprocedure.

One anterior platen is used for the anterior side of patients and alsohas two telescoping devices to provide patients a safe distance awayfrom the COG assembly during the hook-up phase of the transfer. Asafety-belt system (one or more safety belts) is used to engage theposterior platen and the anterior platens together for the rotate, orpatient turning, phase. Padding may be coupled to the safety-belt systemto help ensure appendages of the patient are secured while rotated.

Pre-stage conditions for an illustrative embodiment describe specificsof the lowering function, latching of COG assembly to posterior andanterior platens, COG self centering features, COGassembly-self-centering-ratchet-and pawl-functions, and finally thespindle-lost motion functions. More particularly, the pre-stageconditions are: (1) the posterior platen is manually pre-staged onto theoperating room (OR) table and each telescopic end of the platen isadvanced into a locked position; (2) a patient is positioned on top ofthe posterior platen for rotation into the prone position; (3) the upperand lower dual-rack-and-pinion shafts of each COG assembly are extendedand locked into their fully extended positions; (4) the anterior platenassembly is already locked onto its respective COG latches and isrotated in a ready-to-receive position over the top of the patient lyingon the posterior platen and operating table; (5) the floor frame systemhas already been located to the lower platen with a caster-base-mountedregistration plate; (6) all casters are locked in-position; and (7) thelinear actuator drive is powered-on.

In practice, a staff member of the hospital or similar facility controlsa pendant button in order to lift or lower platens onto or off from theoperating table. When the pendant button (or other suitable controlmechanism) for lowering is actuated, both linear actuator devices lowersimultaneously with respect to each other. The pendant button isdepressed and two lift columns lower the COG assemblies. Theanterior-frame latch mechanism mounted on each of the COG assembliesfully nest over the platen tubes during this downward motion. Oncecontact with the platen tubes has occurred, the dual rack and pinionsystem of the COG assemblies begins to close and theCOG-assembly-release-mechanism ratchet-and-pawl device begins toback-drive and the platens adjust themselves to the size of patient(vertical thickness). During this downward self-adjusting motion, theanterior platen foam pads eventually make contact with the patient and acontrolled patient pad compression is reached. The anterior platen, thetwo COG assemblies, and the two spindle assemblies stop lowering whilethe linear motion columns are free to continue traveling until a limitswitch is made (approximately two inches of travel). This provides asafe and reliable system for patients, and provides staff members withpeace of mind that this system can safely perform its function.

The posterior platen is latched onto the dual-rack-and-pinion shafts ofthe COG assembly. The pad compression system is checked and adjusted bymanually pulling the anterior platen down until a safe amount of padcompression is achieved. Next, safety belts are attached to the mushroomhead pins and belts are cinched to secure the patient. Finally the liftand rotate functions are achieved.

Further details and advantages of a patient transfer system will becomeapparent with reference to the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is presented with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. It isemphasized that the various features in the figures are not drawn toscale, and dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 shows a perspective view of an exemplary patient-safety-transfersystem.

FIG. 1A shows a side view a center-of-gravity assembly coupled to aspindle assembly, which is mounted on an inside portion of apowered-lift column.

FIG. 2 is a top-outline view of a platen.

FIG. 2A shows a portion of an exemplary safety-belt system of thesystem, connected to grooves of the platens.

FIG. 3 shows a cut-away view of a COG assembly illustrating thedual-rack-and pinion arrangements, gas-shock absorber, andanterior-and-posterior-platen-latch mechanisms.

FIG. 4 shows a see-through version of a COG assembly.

FIG. 5 shows placement of the control knobs for the hook latches of theplaten latch mechanism.

FIG. 6 shows an isometric view of the posterior-platen-latch mechanismcoupled to the lower rack shafts of the COG assembly and further coupledto the posterior-platen-tube assembly.

DETAILED DESCRIPTION

Reference herein to “one embodiment”, “an embodiment”, or similarformulations, means that a particular feature, structure, operation, orcharacteristic described in connection with the embodiment, is includedin at least one embodiment. Thus, the appearances of such phrases orformulations herein are not necessarily all referring to the sameembodiment. Furthermore, various particular features, structures,operations, or characteristics may be combined in any suitable manner inone or more embodiments.

Terminology

The expression “center-of-gravity” refers to the point at which theresultant gravitational force acts upon an object. The center of gravityis not necessarily inside the object. For example, the center of gravityof a ring is at the center of symmetry. If the geometry of the objectdoes not change with time, the center of gravity will remain unchangedin relation to the object. In embodiments described herein, thecenter-of-gravity changes as patients placed in and removed from thesystem.

As used herein the expression “operating table” refers to generaloperating room tables, medical procedural tables, x-ray tables, andpotentially other surfaces for performing a medical procedure usuallyunder sedation and/or general anesthesia. The term “gurney” and“gurney-like,” refers to a mobile platform used in a facility, such as ahospital, to move a patient that is lying down.

The term “over travel”, as used herein refers to the distance over whichthe moving member(s) travel after a platen has come to rest on a supportstructure.

The term “platen”, as used herein refers to an assembly having aframework and a patient support area disposed within an area defined bythe framework. The term “anterior platen” generally refers to the platenwhich is configured to support the anterior side of a patient. The term“posterior platen” generally refers to the platen which is configured tosupport the posterior side of the patient. While specific examples mayrefer to one or the other, it should be appreciated by those skilled inthe art, that either platen is interchangeable with the other, and suchterminology is not necessarily intended to limit the scope of theclaims.

The term “prone” refers to a patient lying face downward.

The term “supine” refers to a patient lying face upward.

The expression “ratchet-and-pawl system” refers to a mechanism havingthe ability to back-drive in one direction and catch in the oppositedirection of rotation.

System Overview

Described herein is a patient-safety-transfer system configured to lift,rotate, and transfer a patient to/from an operating table. An embodimentof the patient-safety-transfer system 100 is depicted in FIG. 1. Theprimary components of system 100, include a chassis 101, powered-liftcolumns 102(1), 102(2), center-of-gravity (COG) assemblies 106(1),106(2), spindle assemblies 108(1), 108(2), portable-caster-baseassemblies 110(1), 110(2), a drawbar 112, a posterior platen 114, ananterior platen 122, and registration plates 126(1), 126(2).

Chassis 101 serves as a framework for apparatus 100, which is configuredto straddle an OR table. Chassis 101 includes two portable-caster-baseassemblies 110(1), 110(2). Portable-caster-base assemblies 110 arecoupled to each other by drawbar 112. Drawbar 112 includes an operatingposition, and a second collapsible-storage position. In thecollapsible-storage position, drawbar 112 slidably folds together, whichenables storage or transportation of system 100.

Powered-lift columns 102(1), 102(2), in embodiments described herein,are typically electrically powered, but it is appreciated by thoseskilled in the art having the benefit this disclosure, that thesepowered-lift columns are not so limited and may be powered by anysuitable means including but not limited to hydraulics and pneumatics.102(1), 102(2) are located at distal ends of drawbar 112. Powered-liftcolumns 102(1), 102(2) vertically extend and retract allowing foradjustability in height of platens 114 and 122. In one embodiment, theheight of both powered-lift columns 102(1), 102(2) move in unison.Powered-lift columns 102 may incorporate actuators (not shown) thattelescopically expand and contract each column to control their height.

Attached to the powered-lift columns 102 are a pair of rotation systemsincluding COG assemblies 106(1), 106(2) each coupled to respectivespindle assemblies 108(1), 108(2) (which are obstructed in FIG. 1). FIG.1A shows a side view a COG assembly 106 coupled to a spindle assembly108, which is mounted on an inside portion of powered-lift column 102.Still referring to FIG. 1A, each COG assembly 106 includes internalassemblies (to be described) which facilitate the securing of a patientbetween posterior and anterior platens 114 and 122 (shown in FIG. 1).Each COG assembly 106 includes two opposing pairs of latch assemblies160(1), 160(2) for releasably connecting posterior platen 114 andanterior platen 122 to system 100. Because of the side view, in FIG. 1A,only two out of the four latch assemblies can be seen.

Referring to FIG. 2, is top-outline view of a platens 114/122. At thedistal ends 200(1), 200(2) of platen 114/122 are extension telescopingshafts 202(1), 202(2), 202(3), 202(4). Connected to the telescopingshafts 202 are platen tubes 204 (1), 204(2), which are generallyperpendicular to the telescoping shafts 202. Telescoping shafts 202slide in and out of platens 114/122. When connected to COG assemblies106 (FIG. 1), telescoping shafts 202 are extended several inches. Whendisconnected from COG assemblies 106, telescoping shafts 202 may beretracted so that these shafts 202 and platen tubes 204 may becoextensive or in the boundaries of the operating-table surface.

Referring back to FIG. 1A, each of latch assembly 160 releasablyattaches to platen tubes 204. Each spindle assembly 108 is mounted on atop portion of each column 102. COG assembly 106 is mounted to aninboard side of each spindle assembly 108 with a spindle shaft 210allowing for rotation of the COG assembly 106. COG assembly 106 adjustsa latching open and shut with a dual rack and pinion device to open bothor close both posterior and anterior shafts simultaneously. A platenlatch assembly is mounted to each end of the COG assembly in order tomanually lock onto the platen tubes. Each COG assembly has one platenlatch assembly for the posterior platen and one latch assembly for theanterior platen. One posterior platen is used for the posterior side ofpatients and has two telescoping shafts to provide a safety distance(approximately 6.0 inches) between the COG platen latches and thepatient, while the patient is lying on the platen. Platen tubeextensions can be collapsed when a transfer or rotation is complete inorder to provide patient access during an operating room procedure. Oneanterior platen is used for the anterior side of patients and also hastwo telescoping devices to provide patients a safe distance away fromthe COG assembly during the hook-up phase of the transfer. One safetybelt system is used to engage the posterior platen and the anteriorplatens together for the rotate, or patient turning, phase.

Referring back to FIG. 1, occipital padding 170 and a leg bolster 172may be placed on a planar surface of anterior platen 122 to support thehead and legs respectively when a patient lies on his back on thesurface of platen 114, and provide friction support to secure thepatient disposed between the platens 114/122, when rotated 180 degrees.

Anterior platen 122 includes a removable head-support assembly (notshown), a torso support 174, and leg pads 176 and 178 which support thepatient while laying in a prone position, and provide friction supportto secure the patient disposed between the platens 114/122, when rotated180 degrees. Torso support 174 and leg pads 176, 178 are attached torails 180(1), 180(2), and can slide longitudinally along rails 180 viabrackets 182 that fit around rails 180.

A groove 184 located on each side of platens 114, 122 permits asafety-belt system (one or more safety belts 186) to be slidablyattached to grooves 184 of both platens 114, 122. FIG. 2A shows a sideview of a portion of platens 114, 122 showing an exemplary safety-beltsystem connected to grooves 184. Because the release latches of eachsafety belt 186 are attached proximal or directly to at least one groove184 of a platen (in this example 114), only one portion of the two-piecebelts may hang down or be conveniently folded under/over a platen114/122 and out of the way when not in use. This eliminates medicalpersonnel having to deal with two portions of a safety belt, and reducesoverall ease and operation of system 100 when connecting anddisconnecting platens 114 to 122 using the safety-belt system. In oneembodiment, safety belts use mushroom-head pins. With reference to FIG.1, side padding 190 may be attached to portions of one or more safetybelts to fasten the arms of a patient and provide redundant security toprevent a patient from falling out of system 100 when rotated 180degrees.

Torso support 174 consists two pads in the general shape ofWilson-styled chest frame which supports the outer portions of the sideof patient. These pads extend from the upper thighs to the shoulders ofa patient. The height of the center portion of the torso support isadjustable by a manual or powered crank system.

Generally, system 100 eliminates the need for operating room staff tomanually lift and place patient on and off an operating table.

Various embodiments disclosed herein include several mechanicalelements, assemblies and subsystems, such as, but not limited to,dual-rack-and-pinion subsystems, lost-motion devices, gas-shockabsorbers, and ratchet-and-pawl subsystems. These mechanical elements,assemblies, and subsystems are combined in a unique manner to provide apatient-safety-transfer system 100 operable to safely rotate a patientfrom a supine to prone position, and from a prone to supine position.

Regarding the dual-rack-and-pinions in embodiments to be described, eachof these allow a top set of racks to extend simultaneously with a lowerset of racks comprising the dual-rack-and-pinions. This is used in eachCOG assembly (described in greater detail below) and provides a selfcentering function. With respect to lost motion devices, in mostapplication the driven load stops moving when it contacts a fixed stopand the powered device (i.e., columns 102) continue to lower in a freestate.

Gas-shock absorbers (described in greater detail below) are used tocounter-act large weights in many mechanisms such as a rear hatch doorin a vehicle. The gas-shock absorbers are sized to each application inorder to reduce free energy caused by gravity as well as provide anergonomic, realistic amount of energy for human beings to safely performa given manual function, such as, rotating a patient from supine toprone and vice versa.

Ratchet-and-pawl systems provide mechanisms with the ability toback-drive in one direction and catch in the opposite direction ofrotation as is used in COG assemblies 106.

Pre-stage conditions for an illustrative embodiment of the presentinvention are set as listed below in order to facilitate detaileddescriptions of the specifics of the lowering function, latching of COGto posterior and anterior platens, COG self centering features, COGassembly self-centering-ratchet-and-pawl functions, and finally thespindle lost motion functions. More particularly, the pre-stageconditions are: (1) posterior platen 114 is manually pre-staged onto theOR table and each telescopic end 202 (FIG. 2) of platen 114 is advancedinto a locked position; (2) a patient is positioned on top of posteriorplaten 114 for rotation into the prone position; (3) the upper and lowerdual-rack-and-pinion shafts 302 and 303 (FIGS. 1A and 3) (to bedescribed) of each COG assembly are extended and locked into their fullyextended positions; (4) anterior-platen 122 is already locked onto itsrespective latches 160 (FIG. 1A) and is rotated in a ready-to-receiveposition over the top of the patient lying on posterior platen 114 andoperating table (not shown); (5) portable-caster-base assemblies 110have already been located to posterior platen 114 with registrationplate 126 mounted to inbound portion of columns 102; and (6) casters arelocked in-position.

In practice, a staff member of the hospital or similar facility controlsa pendant-control panel (not shown) in order to lift or lower platensonto or off from the operating table. When the pendant button forlowering is actuated, both columns 102 lift and lower simultaneouslywith respect to each other. The pendant button is depressed and the twolift columns lower the COG assemblies 106. Latch mechanisms 160 mountedon each of the COG assemblies fully nest over the platen tubes 204 (FIG.1A) during this downward motion. Once contact with platen tubes 204 hasoccurred, dual-rack-and-pinion system of COG assemblies 106 begins toclose and a release mechanism of a ratchet-and-pawl assembly begins toback drive and platens 114/122 adjust themselves to the size of patient(vertical thickness). During this downward self adjusting motion,anterior-platen-foam pads (such as on torso support 174 and leg pads176, 178 depicted in FIG. 1) eventually make contact with the patientand a controlled patient pad compression is reached. Anterior platen122, COG assemblies 106, and spindles assemblies 108 stop lowering whilethe linear motion of columns 102 are free to continue traveling until alimit switch (not shown) is made (approximately two inches of travel).This provides a safe and reliable system for patients, and providesstaff members with peace of mind that this system can safely perform itsfunction.

Posterior platen 114 is manually latched onto dual rack and pinionshafts 301, 302 (FIG. 1A and FIG. 3) of the COG assembly 106. Next,safety belts 186 (FIGS. 1 and 2A) are attached and cinched toredundantly secure the patient (in addition to the compression of thepadding against the front and back of the patient). Finally the lift androtate functions are achieved.

Lost Motion System

Spindle assembly 108 mounts on a top portion of lift column 102. In afirst case, when lift columns 102 are raised, spindle assemblies 108stay in contact with the top portion of lift column 102, and thereforeCOG assemblies (each coupled to the inboard spindle 210 (FIG. 1A) ofeach of the spindle assembly 108) and platens 114/122 (each coupled toplaten-latch mechanisms 160 (FIG. 1A) of COG assemblies 106), areraised.

In a second case, when powered-lift columns 102 are lowered, spindleassemblies 108 stay in contact with the top portion of their respectivelift columns 102, and therefore the COG assemblies 106 and platens114/122 are lowered.

In a third case, when the powered-lift columns 102 are lowered, (i) theplaten-latch assemblies 160 are nested on the platen-tube extensions204, (ii) each COG assembly 106 begins to collapse on itself, (iii)patient-pad contact is made and (iv) platens 114/122, COG assemblies106, and spindle assemblies 108 stop lowering when columns 102 lower andstop based on contacting an internal limit switch (not shown).

Adjustable COG Assembly

An adjustable COG assembly 106 is mounted to the inboard side of eachspindle assembly 108 with a spindle 210 allowing for rotation of COGassembly 106.

Referring to FIG. 3, an illustrative COG assembly 106 is shown with anupper pair of rack shafts 301 a and 301 b at least partially disposedwithin a housing 302 of COG assembly 106. Rack shafts 301 a and 301 bare spaced apart from each other by a first distance, and are also eachcoupled to an anterior-platen latch 315. A lower pair of rack shafts 303a and 303 b are at least partially disposed within housing 302. Lowerpair of rack shafts 303 a and 303 b are spaced apart from each other bya second distance, and are also each coupled to a posterior-platen latch316. Rack shafts 301 a and 303 a are each coupled to a pinion gear 306 ato form a first dual rack and pinion arrangement. Rack shafts 301 b and303 b are each coupled to a pinion gear 306 b to form a second dual rackand pinion arrangement. A gas-shock absorber 314 is disposed in housing302 and has a piston 310 coupled to anterior platen latch 315. A releaseknob 304 provides a mechanism to release rack shafts 301 a, 303 a, 301b, 303 b in order to expand to their fully extended positions. Latchhooks 308 are mounted to anterior platen latch 315, and in operationlatch onto the frame of an anterior platen. Latch hooks 309 are mountedto posterior-platen latch 316, and in operation latch onto the frame ofa posterior platen. A latch-and-pawl-system disposed within housing 302provides a mechanism for the rack and pinion system to collapse andback-drive the pawl mechanism in one direction (i.e., collapse directionof the racks).

COG assembly 106 adjusts open and shut with a dual-rack-and-piniondevice to open both or close both posterior and anterior shaftssimultaneously. As noted above, platen latch assemblies 315, 316 aremounted to each end respectively of the COG to manually lock onto theplaten frames. There is one latch assembly for the posterior platen andone latch assembly for the anterior platen.

Gas-shock absorber 310 performs two functions. The first function is toexpand the COG assembly 106 to pre-stage for a pick-up condition. Thesecond function is to provide a metered support force onto a platen(usually the upper platen) when columns 102 are lowering and platen padsmake contact with the patient. These shock absorbers 310 will supportthe majority of the weight of spindle assemblies 108, COG assemblies106, and a portion of the anterior or posterior platens 114/122.

Each end of COG assembly 106 has a platen-latch assembly (anteriorplaten latch 315 and posterior platen latch 316 respectively). Aftereach column 103 is completely lowered and located onto the tube 204 ofthe posterior platen and the lost-motion limit switch is made, staffmembers, or operators, manually turn either one of knobs 502 (FIG. 5) oneither side of the posterior-platen latch to engage and clamp onto thelower platen tube assembly 602 (FIG. 6). Final patient compression isvalidated by pressing down on both sides of the anterior platen andattaching belt systems between the posterior and anterior platens.

FIG. 4 shows a see-through version of COG assembly 106.

In one illustrative embodiment, a system for turning a patient from asupine to prone position and from a prone to supine position, includes afirst-lifting column having top end and a bottom end; a second-liftingcolumn having a top end and a bottom end; a first-spindle assemblydisposed over the top end of the first-lifting column; a secondspindle-assembly disposed over the top end of the second-lifting column;a first-COG assembly coupled to the first-spindle assembly; a second-COGassembly coupled to the second-spindle assembly; a posterior platenhaving a first-frame assembly, the first-frame assembly coupled to aposterior-platen latch assembly of the first-COG assembly, and furthercoupled to a posterior-platen-latch assembly of the second-COG assembly;an anterior platen having a second frame assembly, the second-frameassembly coupled to an anterior-platen latch assembly of the first-COGassembly, and further coupled to an anterior-platen latch assembly ofthe second-COG assembly; and a safety-belt system coupled between theanterior-platen and the posterior platen.

Some embodiments also include a first-caster base coupled to the bottomend of the first-lifting column; and a second-caster base coupled to thebottom end of the second lifting column.

Still other embodiments include a drawbar coupled between thefirst-caster base and the second-caster base, wherein the drawbar isoperable to maintain the coupling of the first and the second-liftingcolumns while changing the distance between the first and thesecond-lifting columns by telescoping.

In some of these embodiments, each COG assembly includes a housing; amupper pair of racks, each disposed at least partially within thehousing, each coupled to one of a corresponding first pair of pinions,and each of the upper pair of racks spaced apart from each other by afirst distance; a lower pair of racks, each disposed at least partiallywithin the housing, each coupled to one of a corresponding second pairof pinions, and each of the lower pair of racks spaced apart from eachother by a second distance; wherein the first distance is greater thanthe second distance.

In another illustrative embodiment, an apparatus suitable for formingpart of a patient turning system, includes a COG assembly coupled to aspindle, thereby allowing the COG assembly to rotate about an axisdefined by the spindle; a spindle assembly upon which the spindle isattached; a lifting column having a first end and a second end, with thespindle assembly disposed upon the first end; and a caster base to whichthe second end of the lifting column is attached.

In some embodiments, the caster base includes an attachment point for adrawbar. The lifting column is operable to move the spindle assemblythereby changing the vertical position of the spindle assembly. The COGassembly includes a housing; an upper pair of rack shafts, each disposedat least partially within the housing, each coupled to one of a pair ofpinion gears, and each of the upper pair of racks spaced apart from eachother by a first distance; a lower pair of rack shafts, each disposed atleast partially within the housing, each coupled to one of the pair ofpinion gears, and each of the lower pair of racks spaced apart from eachother by a second distance; and a gas shock absorber, disposed in thehousing and mechanically connected to the anterior-platen-latchassembly; wherein the first distance is greater than the seconddistance; and wherein a first one of the upper pair of rack shafts and afirst one of the lower pair of rack shafts are each coupled to afirst-pinion gear of the pair of pinion gears in afirst-dual-rack-and-pinion arrangement, and a second one of the upperpair of rack shafts and a second one of the lower pair of rack shaftsare each coupled to a second pinion gear of the pair of pinion gears ina second-dual-rack-and-pinion arrangement. It is noted that the ends ofthe first-dual-rack-and-pinion arrangement and the ends of the seconddual rack and pinion arrangement all expand and collapse simultaneouslywith each other.

Conclusion

The exemplary methods and apparatus illustrated and described hereinfind application in at least the field of patient safety transportsystems.

It is to be understood that the present invention is not limited to theembodiments described above, but encompasses any and all embodimentswithin the scope of the subjoined Claims and their equivalents.

1. An apparatus for turning a patient from a supine to prone positionand from a prone to supine position, comprising: a first-lifting columnhaving a top end and a bottom end; a second-lifting column having a topend and a bottom end: a first-spindle assembly disposed over the top endof the first-lifting column; a second-spindle assembly disposed over thetop end of the second-lifting column; a first-COG assembly coupled tothe first-spindle assembly; a second-COG assembly coupled to thesecond-spindle assembly; a posterior platen having a first-frameassembly, the first-frame assembly coupled to a posterior-platen-latchassembly of the first-COG assembly, and further coupled to a lower-latchassembly of the second-COG assembly, the posterior platen having apatient support area; an anterior platen having a second-frame assembly,the second-frame assembly coupled to an anterior-platen-latch assemblyof the first-COG assembly, and further coupled to ananterior-platen-latch assembly of the second-COG assembly, the anteriorplaten having a patient-support area; and a safety belt system coupledbetween the anterior platen and the posterior platen, wherein the firstCOG assembly comprises: a housing; an upper pair of rack shafts, eachdisposed at least partially within the housing, each coupled to one of apair of pinion gears, and each of the upper pair of rack shafts spacedapart from each other by a first distance; a lower pair of rack shafts,each disposed at least partially within the housing, each coupled to oneof the pair of pinion gears, and each of the lower pair of racks spacedapart from each other by a second distance; and a gas shock absorber,disposed in the housing and mechanically connected to the anteriorplaten-latch assembly; wherein the first distance is greater than thesecond distance; and wherein a first one of the upper pair of rackshafts and a first one of the lower pair of rack shafts are each coupledto a first-pinion gear of the pair of pinion gears in afirst-dual-rack-and-pinion arrangement, and a second one of the upperpair of rack shafts and a second one of the lower pair of rack shaftsare each coupled to a second-pinion gear of the pair of pinion gears ina second-dual-rack-and-pinion arrangement.
 2. The apparatus of claim 1,wherein the first lifting column and the second lifting column are eachelectrically powered.
 3. An apparatus for turning a patient from asupine to prone position and from a prone to supine position,comprising: a first-lifting column having a top end and a bottom end; asecond-lifting column having a top end and a bottom end; a first-spindleassembly disposed over the top end of the first-lifting column; asecond-spindle assembly disposed over the top end of the second-liftingcolumn; a first-COG assembly coupled to the first-spindle assembly; asecond-COG assembly coupled to the second-spindle assembly; a posteriorplaten having a first-frame assembly, the first-frame assembly coupledto a posterior-platen-latch assembly of the first-COG assembly, andfurther coupled to a lower-latch assembly of the second-COG assembly,the posterior platen having a patient support area; an anterior platenhaving a second-frame assembly, the second-frame assembly coupled to ananterior-platen-latch assembly of the first-COG assembly, and furthercoupled to an anterior-platen-latch assembly of the second-COG assembly,the anterior platen having a patient-support area; and a safety beltsystem coupled between the anterior platen and the posterior platen,wherein the first frame assembly includes two telescoping shafts, andthe second frame assembly includes two telescoping shafts.
 4. Theapparatus of claim 3, further comprising: a first-caster base coupled tothe bottom end of the first-lifting column; and a second-caster basecoupled to the bottom end of the second-lifting column.
 5. The apparatusof claim 4, further comprising: a drawbar coupled between thefirst-caster base and the second-caster base; wherein the drawbar isoperable to maintain the coupling of the first and the second liftingcolumns while changing the distance between the first and the secondlifting columns by telescoping.
 6. The apparatus of claim 3, wherein thetelescoping shafts are collapsible to eliminate patient accessimpediments presented by the outwardly extended telescoping shafts. 7.The apparatus of claim 3, wherein the two telescoping shafts of thefirst frame assembly are in an outwardly extending configuration tocouple with the lower latch assembly of the first COG assembly and thelower latch assembly of the second COG assembly.
 8. The apparatus ofclaim 3, wherein the two telescoping shafts of the second frame assemblyare in an outwardly extending configuration to couple with the upperlatch assembly of the first COG assembly and the upper latch assembly ofthe second COG assembly.
 9. The apparatus of claim 3, wherein thetelescoping shafts of the posterior platen extend outwardly from theposterior-platen-patient-support area by a distance suitable to providea safe distance away from the first and the second COG assemblies forthe patient; and the telescoping shafts of the anterior platen extendoutwardly from the anterior-platen-patient-support area by a distancesuitable to provide a safe distance away from the first and the secondCOG assemblies for the patient.
 10. An apparatus suitable for formingpart of a patient turning system, comprising: a COG assembly coupled toa spindle, thereby allowing the COG to rotate about an axis defined bythe spindle; a spindle assembly upon which the spindle is attached; alifting column having a first end and a second end, with the spindleassembly disposed upon the first end; and a caster base to which thesecond end of the lifting column is attached, wherein the COG assemblycomprises: a housing; an upper pair of rack shafts, each disposed atleast partially within the housing, each coupled to one of a pair ofpinion gears, and each of the upper pair of racks spaced apart from eachother by a first distance; a lower pair of rack shafts, each disposed atleast partially within the housing, each coupled to one of the pair ofpinion gears, and each of the lower pair of racks spaced apart from eachother by a second distance; a gas-shock absorber, disposed in thehousing and mechanically connected to the anterior-platen-latchassembly; an anterior-platen-latch assembly coupled to the upper pair ofrack shafts; and a posterior-platen-latch assembly coupled to the lowerpair of rack shafts; wherein the first distance is greater than thesecond distance; and wherein a first one of the upper pair of rackshafts and a first one of the lower pair of rack shafts are each coupledto a first-pinion gear of the pair of pinion gears in afirst-dual-rack-and-pinion arrangement, and a second one of the upperpair of rack shafts and a second one of the lower pair of rack shaftsare each coupled to a second pinion gear of the pair of pinion gears ina second-dual-rack-and-pinion arrangement.
 11. The apparatus of claim10, wherein the caster base includes an attachment point for a drawbar.12. The apparatus of claim 10, wherein the lifting column is operable tomove the spindle assembly thereby changing the vertical position of thespindle assembly.
 13. The apparatus of claim 10, wherein the ends of thefirst-dual rack-and-pinion arrangement and the ends of thesecond-dual-rack-and-pinion arrangement all expand and collapsesimultaneously with each other.
 14. The apparatus of claim 13, furthercomprising a ratchet-and-pawl system coupled thefirst-dual-rack-and-pinion arrangement and further coupled to thesecond-dual-rack and-pinion arrangement.
 15. The apparatus of claim 14,further comprising a release knob coupled to the ratchet-and-pawlsystem, the release knob operable to release the first and thesecond-dual-rack-and-pinion arrangements and permit the rack shafts tomove into the fully extended position.